


Probably Not What They Meant By a Game Of Cat and Mouse

by leveragehunters (Monkeygreen)



Series: A Game of Cat and Mouse [1]
Category: Captain America (Movies)
Genre: Ableist Language, Alternate Universe - Animals, Alternate Universe - Modern with Magic, Alternate Universe - Modern: No Powers, Beefy Bucky, Bucky is a cat, Cats, Crack, Familiar Bucky Barnes, Fluff, Humor, I didn't actually think that would be a tag, Light Angst, M/M, Magical Realism, Mice, Ridiculous, Skinny Steve, Steve is a mouse, Witch Natasha Romanov, animal to human transformation, only a bit though, t for language
Language: English
Status: Completed
Published: 2017-05-04
Updated: 2017-05-04
Packaged: 2018-10-27 07:38:33
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,790
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10804767
Author URL: https://archiveofourown.org/users/Monkeygreen/pseuds/leveragehunters
Summary: Once upon a time in an apartment block in the city there lived a cat named Bucky and a mouse named Steve.Everyone knows cats and mice can't be friends. But Bucky's not a normal cat: he's a witch's familiar and a damn good one (just ask him). And Steve's not a normal mouse. He's...well, he's Steve.This is their story.(Contains many true mouse facts for your edification.)





	Probably Not What They Meant By a Game Of Cat and Mouse

**Author's Note:**

  * Translation into 中文 available: [盾冬冬盾无差小甜饼 非常猫和老鼠](https://archiveofourown.org/works/11290479) by [mingmingmie](https://archiveofourown.org/users/mingmingmie/pseuds/mingmingmie)



> I don't know what to tell you. I have neither excuse nor explanation. I do blame galwednesday a little bit, since she kinda encouraged me ages ago. Anyway, your first true mouse fact is this: male mice do not have nipples.
> 
> OH, there's _art_ , because I'm blessed beyond what I could ever possible deserve and fandom is filled with generous, talented amazing people:
> 
> [Nipples!](http://koreanrage.tumblr.com/post/161999426925/okay-so-i-read-the-cutest-fic-the-other-day-where) by [koreanrage](http://koreanrage.tumblr.com)  
> [Squeak](http://ellebeesknees.tumblr.com/post/166825774777/lenadrawsinktober-day-26-squeak-dedicated-to) by [lenadraws](http://lenadraws.tumblr.com)

**_Now_ **

"What are _these_?" Steve was staring, appalled, at the little nubs of flesh on his naked chest.

Bucky eyed him. "What do you mean _what are these_ , they're nipples. Did the transformation mess with your brain?"

Steve poked them in confusion. "Why are they sticking out of _me_?"

"What are you talking about? They're nipples. Sticking out is what they _do_. Look." He dragged his shirt up. "See? I have them, too. Okay, only two, not as many as I'm supposed to have, but it's perfectly normal."

"It's really not," Steve muttered, but he crossed his arms and stopped poking at his nipples.

"What, are you telling me you don't normally have them?"

"No, because I'm a _boy_ ," he gave Bucky a look like _Bucky_ was the stupid one here; if Bucky had still been a cat he'd have lashed his tail, "and boys don't have nipples."

It was Bucky's turn to stare in confusion. "Seriously?"

"Why would we?"

Changing Steve into a human had _seemed_ like a good idea... Okay, scratch that. It hadn't seemed like a _good_ idea. It had seemed like _an_ idea, the only one on offer, and Steve hadn't hesitated, but Bucky hadn't expected them to wander down a nipple-laden primrose path. "Okay, you know what? We've now talked about nipples for way too long. You didn't turn human to talk about cat versus mouse versus human anatomy. We've got to go and rescue Natasha."

Steve squared his shoulders with a determined nod and Bucky tossed him a shirt. It was going to be too big, because Steve as a human was a lot like Steve as a mouse—except with nipples, apparently,  _and_ _Bucky, could you stop?—_ small and skinny, but it had never stopped him when he had paws and a tail and Bucky knew it wouldn't stop him now.

When he got the shirt stuck over his head, Bucky sighed fondly and helped him, tugging it into place, then held out the pants. He had to crouch in front of Steve and tie Steve's shoes, something that wasn't easy with one hand, but still easier for him than for Steve, who'd never worn shoes before. Steve's fingers absently scratching through his hair were only slightly distracting.

"Ready?" Bucky asked, rising to his feet.

"Ready."

"Okay, let's go."

 

* * *

 

**_Then_ **

Bucky had first caught wind of Steve when the Asshole had moved in upstairs with his girlfriend. What the Girlfriend was doing with the Asshole, Bucky wasn't sure, but humans could be kind of a mystery sometimes.

He didn't mind the Girlfriend; she'd sometimes stop and scratch him behind the ears if she saw him on the street, tell him what a handsome kitty, what a brave kitty, he was getting by with only one front leg. Bucky _hated_ being called a kitty, but he quite liked being called brave, and he _was_ handsome, pure muscle under his deep black coat, the white patches on his chest and between his ears startlingly bright, and she had long fingernails that hit just the right spot behind his ears, so in the end he decided it was a wash.

The Asshole, though; he lived up to his name. He'd chuck stuff at Bucky if he saw him on the fire escape. It wasn't the best idea, because Bucky wasn't just a cat. Bucky was a _familiar_ , and a damn good one, thank you, having learned more than a few tricks from his witch. Natasha didn't care if he looked over her shoulder while she worked. She'd taught him to read, taught him to understand, and if the things the Asshole threw at Bucky shifted trajectory to bounce off the windowsill and hurtle right back at him, well, wasn't physics just a mystery wrapped in an enigma.

But the Girlfriend had a pet, a tiny grey mouse in a small metal cage, high up on a shelf, and Bucky was, under everything, still a cat.

One day when the Asshole and his girlfriend were out he gave their apartment window, the one overlooking the fire escape, a stern glare and it opened a crack, enough for him to slip inside. Even with a missing left foreleg it was no challenge to leap up to the shelf and saunter over to peer into the cage.

He expected the mouse to run and hide, to cower in its little house. Instead, it crouched low, black eyes fixed on Bucky, and its—no, Bucky realised, _his,_ definitely his—tail whipped madly back and forth. This was the most aggressive rodent Bucky had ever seen—and that was saying something; he'd taken on sewer rats back when he was a street cat.  Grinning a cat grin, showing just a hint of tooth, he settled down to stare into the cage.

"Mouse," he greeted.

"Cat," the mouse practically hissed, which was a good trick for a word with no sibilants. "You're not gonna take me without a fight."

"Who says I want to take you at all?"

"You're a cat. I'm sure you just wandered in here because you wanted to talk." The mouse's tail rattled back and forth in warning.

"Maybe I did. Maybe I was bored."

The mouse scoffed. "Maybe you were hungry."

"You'd be a lousy meal if I was. There's nothing to you but skin and bones." Bucky stood and pressed his nose against the cage. "Doesn't anyone ever feed you?"

Quick as a striking snake the mouse lunged at him, teeth driving for his nose, and Bucky drew back, shocked. "Maybe I'll try _cat_ , see if that fattens me up."

The mouse was clinging to the bars, glaring at Bucky. Bucky stared back, wondering if the mouse was some kind of lunatic psychopath in a mouse's body, and then he started to purr. "Have you got a name?"

"Why?"

"Well I can't keep calling you _mouse,_ it's rude." He curled his tail around his front paw. "And I like you, I don't want to be rude to you."

The mouse was eyeing him suspiciously. "You like me."

Bucky nodded, still purring.

"You're a cat."

"Great observation skills you have there."

"I'm not telling you my name."

"Why not? What do you think I'm going to do with it?" The mouse didn't seem to have an answer for that, which was probably just as well, since there was actually quite a lot that Bucky could do with his name. "Look, I'll go first. I'm Bucky." Which wasn't his name, not his true name, his familiar name; Bucky wasn't that stupid.

The mouse hopped off the bars of the cage, oozing suspicion, then slowly said, "I'm Steve."

"Good to meet you, Steve. Now seriously. Are they feeding you? No offense, but you're kind of small." He _was_ small, small and bony, whip-thin tail, narrow legs, huge, slightly ragged ears, with big, bright, black eyes and long whiskers.

"Yeah, the woman feeds me. I'm small because I was the runt. It's why she bought me. They were going to feed me to a snake and she," he sat up on his back legs, nose twitching, "didn't want them to, so she brought me home."

A weird dart of anger shot through Bucky at the thought, at the matter of fact way Steve said it, and he shifted a little closer to the cage, making Steve skitter back, then bristle, tail flicking a warning. "Calm down, will you? I'm not going to do anything to you."

"Uh huh. Because you're just a soft gooey kitten. Probably one of those vegetarian cats I've heard so much about. Spend your time dancing around with bunnies and pigeons, right?"

Bucky had never heard anything so sarcastic in his life. He thought he might be in love. "Nope, I'm a proper cat, red in tooth and claw. Me predator, you prey. But you're interesting and, really, you'd barely even be a mouthful. I'd much rather talk to you than eat you."

He half expected Steve to tense up, maybe lunge at him again, but instead he stretched out on the shavings, ears and tail relaxed. "As long as we know where we stand."

And that was how Bucky ended up spending part of most days in the Asshole's apartment.

Talking to a mouse.

It didn't start off part of most days. No, it was just a day here or there, a few minutes for Steve to snark at him, for Bucky to snark back. Gradually, Bucky started staying longer, started visiting more often. He'd catch Steve waiting for him, paws up on the plastic liner of his cage, nose pressed between the bars.

He denied it of course, but Bucky knew.

Some days they'd just talk, or Bucky would talk and Steve would listen. Sometimes Bucky would twist a bit of magic and turn on the TV. Steve couldn't see it—mouse eyesight was not good—but he could listen, and there was usually something on he could enjoy. He was learning about the world and Bucky was learning about Steve.

Steve was smart, he picked things up incredibly fast. If it wouldn't have been incompatible with Bucky's essential feline dignity, he might have admitted that Steve was just as smart as him. He was quick and canny and funny and incredibly brave.

And bored. And lonely. The Girlfriend might have saved him from being snake food but she didn't do anything with him. He just sat in his tiny cage on the shelf with his plastic house and stared out at the world.

It made Bucky sad. It was better than being dead, but it was no life for a mouse like Steve.

 

* * *

 

Inevitably the Girlfriend came to her senses and left the Asshole.

But she also left Steve.

This was something Bucky didn't know right away. The building was alight with gossip about the Girlfriend, since she'd stormed out in a spectacular manner, but the gossip didn't have room in it for a small grey mouse. Bucky spent a week telling himself he was an idiot for missing Steve, for missing _a mouse_ , until he overheard the Asshole mutter about getting rid of that dammed cage because it was starting to stink up the joint.

His heart dropped into his paws and he paced, back and forth, back and forth, waiting for the Asshole to leave for work so he could race up the fire escape and through the suddenly open window and leap up onto the shelf.  

Steve's water bottle was completely dry and there wasn't a scrap of food in his cage. "Steve?" Bucky gently nudged the cage with his nose. " _Steve_."

His head poked out of the house. He looked even skinnier than usual, tail and ears drooping. "Hi Bucky."

"How long has this been empty?" he asked, indicating the water bottle.

"I don't know. A few days?"

He fought back a hiss. "I'm getting you out of here."

There'd always been the cage between them, always been bars. Always been the illusion of safety. Steve looked up at him, normally bright eyes dull. "Okay."

It was easy: grab the latch with his teeth and lift, grab the door with his teeth and pull and it was open. There was nothing between them.

Steve hesitated. He was brave and bold, but he was still a mouse and Bucky was still a cat. "Bucky?"

"I won't hurt you. I promise." He lay down on the shelf. "Can you climb onto me? Up onto my back." He couldn't imagine the courage it took to climb out of the cage and step onto his paw, to climb up his fur and settle between his shoulder blades. He could hear Steve's racing heart, could feel his own instincts trying to rise, saying _mouse,_ saying _prey,_ but he kept them under control, because Steve _wasn't_ prey. Steve was his friend. Steve needed him. If Steve stayed here he was going to die. And that wasn't an option. "Okay?"

"I'm okay."

"Just hang on." He rose to his feet and as delicately as he could he leapt to the couch and to the floor. He felt Steve gripping his fur with his paws, felt the tiny, barely noticeable weight of him. The tiny, barely noticeable _reassuring_ weight of him. "We're going home."

It was a quick trip down the fire escape and into his own apartment. Natasha wasn't there, she was at work, so they had the place to themselves. "What do you need first? Water?"

"Please."

He took Steve to his bowl and let him balance on his paw while Steve drank and drank and drank. And kept drinking and Bucky shuddered at how close he'd come to losing him. When he was done Steve nibbled at a bit of Bucky's food, then stumbled after Bucky and into Bucky's bed, curving into a circle of a mouse, tail draped over his nose. He was asleep in seconds.

Bucky sat next to him. He was going to stay right here, watching over him until he woke up.

If he'd thought it through he might have realised it wasn't the best idea he'd ever had. Looming over a tiny mouse who'd had a really bad week wasn't exactly guaranteed to make him feel _safe._ But Bucky wasn't thinking about that. Bucky was focused on not leaving Steve alone, so he could make sure nothing happened to him, as he tried really hard not to think about what _could_ have happened to him if he hadn't overheard the Asshole.

When Steve woke up an hour later, nose twitching, and lifted his head, he froze, eyes locked on Bucky. Bucky could see his heart pounding as his eyes darted back and forth, searching desperately for an escape route.

"Steve," Bucky said softly. "Steve, you're safe. It's me." He was half-crouched over Steve, like he was about to pounce, but he was afraid to move, afraid if he didn't keep completely still Steve would bolt, disappear into the floor or the walls and Bucky would lose him. "Come on, you know me."

Gradually, the tension seeped out of Steve and he sat up on his back legs, tail curled close around his body, ears drooping. "Sorry, Bucky. I just, I woke up and all I saw was a cat. I'm not," he ran a paw over his ear, looking up at Bucky shamefacedly, "not used to not having bars around me. It's going to take some adjusting."

"Nothing to apologise for." Bucky carefully lay down, settled his head in front of Steve. "I _am_ a cat. Not one who's ever going to hurt you, but still a cat. Makes sense that you'd react to that."

"No it doesn't." Steve's voice was fierce and he bounded forward to put his paws on Bucky's nose. "And it's not okay that I did. You saved me, Bucky. I know it and you know it. I would have died in that cage if you hadn't come for me. It's not right that I acted like you were going to hurt me."

"Go easy on yourself, Steve. Okay?" He breathed out gently, gave Steve a tiny nudge. "You've had a rough time."

Steve sighed and dropped down, then lay down next to Bucky's chin, tail draped over Bucky's paw. "Still doesn't make it right."

A wave of affection puffed through him and he carefully nuzzled Steve. "Mouse for brains."

Steve tilted his head to give him a long stare, then reached up with a paw to tug one of Bucky's whiskers. Bucky began to purr. After a few minutes, he let it die away as the reality of the situation sunk in. Steve was here. Steve was here with him, in his apartment, in _Natasha's_ apartment, and if Bucky had his way he wouldn't be leaving. "You should probably know, I'm not just a cat."

"No, you're _Bucky_. You're way more than just a cat."

He'd be kicked out of the cat club if anyone knew how that made him feel, much less how it made him feel about a _mouse,_ but luckily there was no such thing as the cat club and no one would ever know. "Not what I meant," he said softly, rubbing his nose across Steve's back. "I'm a familiar. Natasha, my person? She's not just my person. She's my witch." He could tell from the way Steve was looking at him that he didn't know what that meant. "She does magic and she uses me to draw power, to help control it."

"She doesn't hurt you, does she?"

"No, never. She loves me. She protects me. She's the one who found me after my leg got ripped off. Car," he added to Steve's questioning look. "She took me in, she got me healed up, and when I was better she asked me if I wanted to be her familiar. It was my choice."

"That's okay, then."

It was pure curiosity, but then Bucky _was_ a cat, that made him ask, "What would you have done if I'd said yes?"

"Figured out a way to get you free."

Bucky stared at Steve—tiny grey mouse, bright black eyes gleaming with reflected light—and realised he believed him. If he'd needed it, Steve really would have tried to set him free. His heart lurched and he rearranged himself to curl around Steve. "You would have, wouldn’t you?"

"Of course." Steve shuffled forward and nestled into the fur of Bucky's belly. "I'm glad I don't have to, because I have no idea how I would've managed it, but I would have tried."

Eventually they fell asleep, Bucky's soft purr filling the air.

The sun was low when Bucky heard his name, a gentle voice winding its way into his dreams. He yawned, almost stretched, then remembered Steve and stopped himself.

"Bucky."

He blinked completely awake to Natasha smiling down at him. Instinctively, he tried to hide Steve, curling tighter around him.

Her smile grew wider. "Who's your friend?"

Bucky hung his head. They were caught. "Steve? You'd better come out."

"I don't want to. She's going to get rid of me." His voice was muffled since he'd wormed his way right up against Bucky's belly.

"She won't, I promise." Bucky nuzzled him. "Trust me."

With a sigh, Steve, feigning boldness Bucky knew he didn't feel, made his way out of Bucky's fur to stand next to Bucky's front paw.

"Well," Natasha said, crouching so she could see him better. "A mouse. Bucky, don't you know you're supposed to hunt mice?"

Bucky's ears flattened and he graced her with his most unimpressed look.

"Not this one, I take it. Is he your pet?"

"I'm not your pet! Tell her I'm not your pet," Steve demanded, sounding outraged.

"I can't actually _talk_ to her. Not like this, anyway. I'd have to change."

"Change?"

"Yeah, change. I can turn into a human."

"What?"

"It's no big deal. It's kind of interesting."

"You can turn into a human and it's _no big deal_?"

"Bucky," Natasha said, snapping her fingers, pulling his attention back. "I take it we're keeping him?"

Bucky started up a deep, rumbling purr and Natasha grinned at him.  

"That's a yes. Can I meet him?"

"What does that mean? Bucky, what does she want?"

He could see Steve was nervous and it suddenly struck him that Steve's entire experience of humans was whoever had wanted to feed him to a snake, the Girlfriend who'd left him in a tiny cage and then abandoned him to die, and the Asshole. "She just wants to get a closer look at you. She won't hurt you." Steve looked between him and Natasha, then took a deep breath and stepped forward, lifting himself up on his back legs and stretching up towards Natasha.

Natasha offered him her finger and he sniffed it delicately. She didn't try and touch him or pick him up, just let him take his time, and eventually he put one paw on her finger and gently nibbled her fingernail, making her grin.

"I like him," she said to Bucky, and Bucky half-closed his eyes, pleased, as Steve hurried back to sit under his chest. "He can't keep living in your bed, though. He's going to need a place of his own. Do you want to change so you can pick it yourself?"

"She means become human, doesn't she?" Steve asked.

"Yeah. Do you mind? If she's serious about getting you somewhere to live I want to make sure it's something you're going to like."

"You'll come back, though." Steve reared up and put his front paws on Bucky's leg. "Right?"

"Of course. I'm not going to leave you." He rasped his tongue across Steve's head, making his ears flatten, but he hunkered down, looking pleased.

Bucky moved across the floor, away from Steve so he wouldn't accidentally crush him, and closed his eyes, reciting the words in his head that would activate the sigil tattooed on his back.

It was itchy and he felt the magic grab him and pull him apart, then stitch him back together in a new shape. He yawned and stretched and blinked, looking around. It was so strange being taller, being _bigger_ , than Natasha, because his human body was all muscle, just like his cat body, and just like his cat body he still only had one front leg. One arm. All the magic did was turn him into a human version of _himself;_  it couldn't make him into something he wasn't and who he was had a missing front limb.  _No big deal._

Natasha tossed a pair of pants at him and he _didn't_ roll his eyes—humans and their hang-ups about clothes and bodies—just pulled them on without complaint, then pulled on the shirt she passed him.

Once he was clothed to Natasha's satisfaction, he crouched down and held out his hand. Steve was so tiny and looked so uncertain, sniffing the air, and Bucky knew he must smell completely different. He lay down on the floor and put his nose against Steve's. "It's still me," he whispered. Steve's whiskers tickled and he fought not to laugh, then offered his hand again and Steve climbed into it. Bucky lifted him and cradled him against his chest.

"Not your pet, then," Natasha said.

"No."

"Where did he come from?"

"The Asshole's girlfriend left him behind. He would've died." He held Steve closer, fingers curled protectively. "I couldn't leave him there."

"Of course you couldn't."

"I don't want him to live in a cage."

"No," Natasha said absently as she fiddled with her tablet. "But he should have a safe place to go that's just his own. Here," she set the tablet on the table, "see what you think he'd," she stopped, "what's his name?"

"Steve," Bucky said fondly, looking down at him. "His name's Steve."

"See what you think Steve would like."

Steve ended up with a large, airy habitat with tunnels and wheels. Natasha left the lid and two of the sides off, installed a ladder that stretched all the way to the floor, and covered the base with soft grey pellets. She bought Steve proper food, with everything a mouse could need, even if she always gave him bits of pasta and vegetables and fruit, and he started to fill out. He'd never be _big,_ but he wasn't quite so skinny, Bucky couldn't see every bone in his tail anymore.

Steve spent time in his habitat, running like crazy on the wheels, so fast he was a blur Bucky couldn't follow, but he never slept there. He always slept with Bucky, snuggled into Bucky's fur or curled into the space between Bucky's front leg and his chest, soothed to sleep by Bucky's rumbling purr.

 

* * *

 

It was a few weeks, Steve settling in and growing more secure, before Natasha needed Bucky to do his job.

Steve perched on the edge of the table to watch, tail held between his paws as he absently groomed it, while Natasha drew power through Bucky. Bucky's fur ruffled like he was standing in a high wind, little sparks of static leaping across his back, but he could feel Natasha weaving what she was pulling through him into something greater than it would have been on its own.

This was what being a familiar was all about. Being part of something greater. His gaze drifted sideways to Steve, who was looking worried, and he let his eyes half-close, started to purr, and saw him relax a little. 

With a pop and the smell of cloves and pine, the magic let him go. He yawned and stretched, then leapt onto the table and sprawled next to Steve, who nestled into the empty space where Bucky's leg used to be.

Natasha shook her head as she looked down at them. "Hungry?" she asked.

Bucky put his head down and closed his eyes. "Sleep first, then food," he muttered. She couldn't understand him, but he knew she'd get the gist.

"You smell like pine," Steve said, wrinkling his nose as Natasha scratched Bucky's ears.

Planting his paw carefully over Steve, he rasped his tongue down Steve's back. "Go to sleep."

"What, now that I'm drowning in cat spit?" Steve sniffed, nose twitching as he groomed his whiskers with his paws, but he sounded pleased.

"Shut up, you love it."

"Just keep telling yourself that," Steve muttered, snuggling closer. "Just keep telling yourself that."

 

* * *

 

It was a month later, Bucky had been out making his presence known on the sidewalks and in the alleys—this was Bucky's neighbourhood and he intended to keep it that way, but that took constant vigilance—when he returned to the apartment to discover his initial impression had been right.

Steve _was_ a lunatic in a mouse's body.

"What the—" Bucky's eyes just about bugged out of his head as he hopped in through the fire escape window and glanced up. "Steve, what the hell are you doing?"

"What?"

Steve's confusion came through loud and clear, which was amazing considering he was about ten feet up, balancing on a wire so thin Bucky could barely see it. Natasha had put it up last year to hang lights from; she'd pulled the lights down when she was done with them but had left the wire in case she needed it again.

 _Not_ for damn fool mice to go wandering on. "Get down from there!"

"Why?"

"Before you fall down!"

"I'm not going to fall."

"Steve, get down here, right now!" Bucky's tail was puffing out with worry.

"So you want me to get down in a rush because you're worried about me falling, instead of making my way back down the same way I got up—carefully?" Bucky was surprised sarcasm wasn't dripping off Steve and into a puddle on the floor.

"Just," Bucky hissed, tail lashing, "just get _down_. Safely!"

He stared hard as Steve scampered across the wire to the curtain rod, took a flying leap onto the curtain, half-climbed, half-slid partway down, jumped off, legs spread wide, to land crouched on the coffee table. He shook himself, ran to the edge, leapt off and landed on the floor. He hurried over to Bucky and sat up on his haunches, tail wrapped around his paws, looking pleased with himself. "Happy now?"

"You just about gave me a heart attack."

"Really?" Steve's eyes gleamed. "Were you worried about me?"

"Yes! New rule: no climbing on things higher than," Bucky looked around, "higher than the fridge."

"Spoilsport."

"I'll spoil your sport," Bucky muttered. "Steve, you're gonna be the death of me."

Steve's ears tilted forward and he crept closer then leaned up to gently pat Bucky's cheek with his paws, running them through Bucky's fur as Bucky dropped his head to meet him. "I'm sorry. But I wouldn't have fallen. It just looked like fun."

Bucky sighed, a gusting breath that fluttered Steve's whiskers. "I've got no problems with fun. Maybe just stick with fun that doesn't have a chance of leaving you splattered across the floor?"

 

* * *

 

For the most part Steve stopped scaring the hell out of Bucky, and for the most part Steve stopped worrying about Bucky channelling Natasha's power.

Bucky knew Steve still wasn't completely at ease with it, but he didn't know how to explain. It was something words couldn't capture, that feeling of being part of something, of power flowing through him, of magic wrapping around him.

Turned out, he didn't need words after all because Natasha invited Steve to _help_. Not like a familiar— _Bucky_ was her familiar, not that he'd mind sharing her with Steve—but there were some workings that were better with three, even if that third was a feisty grey mouse. And while Natasha couldn’t understand Bucky, not unless he changed, Bucky could understand _her_ , understand the magic, and talk Steve through what would happen. When Steve agreed—and Bucky couldn't help wondering if it was so he'd know for sure that Bucky was really okay—he was _actually_ agreeing and that's what mattered; for Natasha's magic, consent was everything.

With power flowing through him into Natasha, his fur ruffling, sparks dancing between him and Steve as Steve hovered at the edges of Natasha's magic, Bucky could see him, could almost touch him. Not the physical Steve, fur and tail and paws and teeth, but _Steve,_ the bit of him that was _who_ he was, the same as there was part of him that was _Bucky_ , that would always be Bucky, no matter what shape the magic gave him.

Bucky saw _Steve_ , brilliant and golden, and he was the most beautiful thing Bucky had ever seen. He wondered if Steve could see _him_ , see _Bucky,_ but, cat or not, for this his curiosity wasn't enough to make him ask.

 

* * *

 

**_Now_ **

Steve had been asleep when Natasha left the message on the answering machine, but he'd woken up quickly enough when Bucky had nudged him with his nose, had immediately offered to be changed when Bucky explained he needed help to rescue Natasha. Animal to human transformation wasn't, technically, the easiest spell in the world, but to Bucky it came as naturally as breathing; he knew it in his bones, it was written on his skin, and it was simplicity itself to use it on Steve.

And now they were here: sitting on a train rattling through the city on the way to rescue Natasha.

They mostly had the carriage to themselves, only a few humans scattered at the other end, all buried in their books or their phones and paying no attention whatsoever to the cat and mouse sitting among them. Steve was curled against his right side, Bucky's arm hanging over his shoulders, Bucky sitting in the aisle seat so Steve could sit closer to the window. "It's so big," Steve said, staring out at the city.

"Yup."

"And it's full of humans."

"Yup."

"Amazing."

"Yup," Bucky said again. He wasn't watching the city, he was watching Steve. Watching Steve's bright blue eyes, reflected in the glass, and his blond hair, which kept falling over his forehead. He'd shove it back and it would stay for a few minutes, then it would fall again. Bucky wanted to run his fingers through it.

The train slowed to a stop, someone got off, someone got on and dropped into the seat across the aisle from them. Bucky ignored him in favour of continuing to watch Steve, who seemed enthralled by the buildings. "They look like my habitat," he murmured. "Only huge."

"Hey." It was the guy who'd gotten on at the last stop. Bucky ignored him. He was a _cat_ ; cats didn't talk to people who _hey'd_ at them. " _Hey_." Rolling his eyes, Bucky shot a disdainful look across the aisle. "What happened to your arm?"

"Are you speaking to me?" Bucky asked.

"I don't see any other cripples around, so I guess I must be." Bucky rolled his eyes again. _Humans._ He wasn't expecting Steve to suddenly tense under his arm as his sharp blue eyes went dark with anger. Wasn't expecting Steve to rise to his feet, fists clenched, chin jutting forward, like he was about to pounce. If he'd had a tail it would have been whipping the air.

"Better get your boyfriend under control," the guy sneered, but Bucky could see his surprise, see he was taken aback by Steve's instant aggression.

Bucky leaned back, feigning relaxation, ready to leap up and reduce the guy to a fine paste if he so much as breathed wrong in Steve's direction. "If anyone's going to be picking their teeth up off the floor, it's not going to be him." He flexed his hand, wishing for claws, and grinned, showing all _his_ teeth, eyes half-lidded.

The guy looked between them, suddenly unsure. "Fuck you guys," he spat, and whirled away to stomp down to the next carriage.

"What a dickhead," Bucky muttered and dragged Steve back down with a fist in his shirt. "Sit. Do not get into fights."

"You heard what he called you." Steve was still vibrating with anger.

"And why should I care what some random asshole says about me?" Bucky yawned, entirely unconcerned, and wrapped his arm around Steve's shoulders, pinning him in place.

"I care," Steve muttered, but he settled, pressed up close into Bucky's side, wiggling a little into the space under his arm. He fit like he was meant to be there and Bucky rested his chin on top of Steve's head.

"I know. But you need to learn to relax. Only fight when it's worth fighting for." Steve mumbled something into Bucky's chest that he couldn't hear. _Damn human ears._ "What was that?"

"I said you're always worth fighting for."

"Aw, Steve. My little mouse." Bucky gave into his previous urge and ran his fingers through Steve's hair. It was soft and Steve pressed into his hand. "I like you like this."

"What, trying to fight people on the train?" His eyes were gleaming as he tilted his head to look up at Bucky.

Bucky rolled his eyes. "No, mouse for brains. Like this." He pulled Steve closer and squeezed him tight. "It'd be better if you were a cat," Steve's stare was suddenly stony, "or not," he backpedalled, fast, "us both being human works just fine."

"Hmmph. _Better if I was a cat_. Better if you were a mouse, you mean."

"No thanks. You don't even have nipples."

They sat in comfortable silence as the city whipped past the window and the train rattled around them. Steve shifted in his seat. "Bucky?"

"Yeah, Steve?"

"I don't know if this is a human thing or not, but I think my balls are broken."

Bucky choked on nothing and stared at the roof of the train, pondering it for several moments until he was sure he could talk without laughing. "In what way," he said, eyes staying right where they were, "are they broken."  

"They don't retract."

"Retract."

"Yeah, no matter what I do they just hang there."

"I take it when you're a mouse you can..."

"Suck them right up, yes. To keep them safe."

Bucky's eyes cut to meet Steve's, to see if he was messing with him—Bucky wouldn't put it past him—but found only honest confusion. "Mice are so weird."

"So it's another human thing."

"Yes," Bucky sighed. "It's another human thing." Not _just_ a human thing; Bucky sure as hell couldn't do it, but somehow he didn't feel any burning need to mention that fact.

Steve snorted and crossed his arms. "Males have nipples they don't need and their balls just hang out where anyone can kick them. How exactly did humans end up in charge of the planet?"

"I ask myself that question every day. And I'm making a new rule: no more talking about nipples or balls." The announcer called their station and Bucky poked him. "Come on, up."

Steve jumped to his feet and Bucky followed, the two of them easily keeping their balance on the swaying train. They hopped off when the train stopped and the doors opened and made their way through the station, Bucky directing Steve with touches on the shoulder, Steve handling both their tickets as they went through the turnstile. They paused when they reached the road, the rush of cars and the sheer mass of people seeming to overwhelm Steve, since he stopped dead and pushed back into Bucky.

Bucky ran his fingers through Steve's hair and whispered in his ear, "Just remember, none of them can suck their balls up," which made Steve laugh. Bucky grinned down at him and pointed his head in the direction they had to go. "Come on."

Steve was alert, staying on Bucky's left, arm bumping against Bucky's side as they walked, head darting this way and that, ears twitching, a stark contrast to Bucky's laconic stroll. Bucky wanted to switch sides with him, so he could wrap his arm around Steve's shoulders, but he studied him, realised Steve was trying to protect his vulnerable side, and he smiled and let it go.

Their destination was in sight, the blue and white sign clearly visible, and Bucky stopped. "Okay. All you need to do is go into that building and tell them that you're there to post bail for Natasha Romanov. They'll tell you what to do from there. Take this," Bucky pulled a wad of cash out of his pocket and tucked it into Steve's, "and this," he held out a black leather billfold that glowed with blue runes he knew Steve couldn’t see. "If they ask you for ID, just show them this. It's magic."

Steve stared down at it but didn't take it. "I thought this was a rescue mission."

"It is. We're rescuing Natasha from the police."

"Why did you need me? Can't you just go in and do all that?"

Bucky scratched his chin with the billfold and avoided Steve's eyes by gazing up into the sky. "Not really. Last time I was here there was an...incident."

"An incident," Steve said flatly.

"Yeah, an incident." Bucky kept avoiding Steve's gaze, which didn't work because suddenly there were strong hands on his cheeks, tilting his head down, and he was very close to Steve's face. Steve still looked like Steve, all sharp angles and bright eyes, even in human shape and Bucky had a very human desire to kiss him. _Stupid human body._ He shook it off. "I may have gotten into a fight with someone who was saying rude things about Natasha when she couldn't do anything about it. I got away with it, but I may not be allowed back into the place or I'll probably get arrested."

"Don't get into fights, huh?"

Steve's fingers were soft against Bucky's skin and his mouth was right there, lips curling at the corners. "I don't care what some random asshole says about _me._ This was different."

"I understand." Steve brushed his thumbs across Bucky's cheeks and Bucky wanted to _purr._ "You wait here." He plucked the billfold from Bucky's hand. "I'll go rescue Natasha."

"Just don't call it that where she can hear you," Bucky called after him. "She'll kill us both!"

He stared after Steve until Steve disappeared into the building, then started pacing the sidewalk. Worrying. He'd just sent a mouse off on his own. Okay, the mouse was Steve, and the mouse was currently human shaped and he'd gone into a police station, so he should be fine, but still. Bucky was worried. He was going to keep worrying until Steve was right back here where he belonged.

 _You do remember you're a cat, right?_ He told himself to shut up. Steve was his mouse, thanks, and he'd worry as much as he wanted.

He breathed a sigh of relief when, twenty minutes later, he saw a familiar flash of red hair and hurried to meet them. Natasha was looking particularly inscrutable. "Bucky," she said, giving Steve a gentle nudge with her hand.

Steve didn't really need the urging, because he was already hurrying forward and Bucky wrapped his arm around him and pulled him into his side, turning his head to press his nose into Steve's hair and breathe deep. "Okay?"

"Okay," Steve replied, leaning against him, fingers tangling in his shirt the same way he wrapped his paws in Bucky's fur.

He looked back to Natasha, who was watching them closely. "Steve was a surprise."

She didn't sound mad, just interested. "The message before yours was Clint saying he was on his way out of town, I can't go in there, and Steve said he'd help. I know how to work the transformation spell, so it made sense."

"And Bucky explained to you what was going to happen?" she asked Steve. Bucky huffed under his breath, mildly offended. As if he'd do _anything_ to Steve that Steve wasn't okay with.

"That it would turn me into a human? Yeah. Bucky warned me it would hurt a little, and it's strange, but," Steve lifted one shoulder and offered Natasha a shy smile, "but you let me stay with Bucky. There's not a lot I wouldn’t do for you. And there's nothing I wouldn’t do for Bucky."

Bucky's heart lurched and he had to force himself not to pull Steve closer and bury his face in his hair. His mouse, his beautiful mouse. Bravest of the brave, boldest of the bold. He could see how touched Natasha was, even though she was trying to hide it, because you can't hide much from a cat.

Or, as it turns out, from a witch.

Natasha gave Bucky a meaningful look before turning to Steve. "You know, Steve, Bucky has a sigil, it lets him become human whenever he wants. If you were interested, I could create one for you."

He felt Steve's heart speed up. "That would be," he looked down at his feet, then glanced at Bucky, "I'd be interested in that. If it wouldn’t be too much trouble."

"Not too much trouble, if Bucky's willing to help me."

Bucky tried hard not to seem too eager as he nodded. Judging by Natasha's smirk, he failed.

 

* * *

 

Natasha, who'd had a long day of protesting and being arrested and bailed out, was napping in her bedroom. Steve and Bucky, still human, were sitting at opposite ends of the couch, bare feet pressed together. "Would she really make me a sigil like yours, so I could be human whenever I wanted?"

"Natasha doesn't offer unless she really means it."

"Why do you think she offered?"

Bucky shrugged, even though he knew damn well why. Bucky was her familiar; she could read him like a book and every page was inscribed with _Steve._  

Steve hummed softly, a low, sweet sound, and curled his toes around Bucky's. "That dickhead on the train."

"What about him?"

"He called me your boyfriend."

Bucky watched him through half-lidded eyes. "He did."

"Why?"

"Because when two humans like each other—" A pillow thumped into his head.

"No, you idiot. I know that. I mean why did he think I was yours?"

"Because of how we were sitting, because I had my arm around you. That's not something humans usually do unless they're together."

"I liked that."

"Being called my boyfriend?"

"Nah, that's just a human word. No, I meant you being close to me. You having your arm around me. I know these bodies aren't our normal ones, but we're still us in them and I like how they fit together. I like how we can touch each other. They're better for that."

Bucky's eyes were full of mischief. "Even with the nipples and the broken balls?"

"Now you're breaking your own rules," Steve pointed out, amused.

"Cat," Bucky replied. "It goes with the territory."

"True."

Steve was watching him hopefully and Bucky felt warmth bubbling up inside him. He pulled his feet away and shifted, moving to plant his knees on either side of Steve's legs. Steve's eyes never left his as he rested his hands on Bucky's thighs. Bucky braced his hand next to Steve's shoulder, leaning down to rub his cheek against Steve's. "I hope you realise this is about the strangest thing either of us has ever done."

"What," Steve slowly ran his hands through Bucky's hair, twirling the strands between his fingers, "fall in love with a cat?"

"Excuse me, falling in love with a mouse is much stranger." Steve started to grin and Bucky lifted his head, looking perplexed. "What?"

"You love me."

"Of course I love you," Bucky huffed.

"I love you, too."

Bucky wanted to leap on top of the nearest fence and sing his joy to the moonlit sky, which would be a bit difficult since it was the afternoon. And he wasn't currently a cat. Something he was incredibly grateful for as he brushed his nose against Steve's. "I know _that_. Are you going to let me kiss you, or what?"

"Since you asked so nicely..." There was the tiniest touch of nervousness in Steve's eyes, in the fingers stroking his neck, and Bucky felt an echo of it. This was new to both of them. His lips were soft when he pressed them against Steve's, just the gentlest touch which Steve tentatively returned. It was slow, each of them learning how it worked, learning how to touch, to taste, bumping noses and teeth and smiling against each other's mouths.

Bucky pulled away briefly to nuzzle Steve's cheek, but Steve caught his mouth again and they had it, yes, this was good, right, _perfect_ , he could feel it racing down his spine and Steve's fingers were curling into his hair, he was nipping at Bucky's lip, he was so _clever,_ and Bucky really wished he had two hands so he could touch him.

He finally lifted his head, because he needed to breathe, and smiled down at Steve, propped himself on his elbow so he could stroke Steve's face, curl his fingers behind Steve's ear, thumb rubbing into the hollow. Steve's eyes were wide and dark and pleased, and he was tugging Bucky back down even as he spoke, one hand curved around the nape of his neck. "I take back everything I ever said about humans. I get why they rule the world."

Bucky buried his face in the crook of Steve's neck, breathing him in, and laughed softly, felt Steve's laughter bubbling up through his chest as Steve stroked his back. This was good, this was better than good, this was everything. This was _Steve._ No matter what, no matter the shape, this was his Steve, golden and brilliant and beautiful. 

**Author's Note:**

> Your second true mouse fact is: Male mice can, indeed, completely retract their testicles into their abdominal cavity. Your third true mouse fact is: scientists have recently discovered that male mice sing to their mates in an attempt to woo them.


End file.
